This invention relates generally to machines for the manufacture of two piece, seamed paperboard cups coated with thermoplastic, and more particularly, pertains to machines for forming a two stage, paperboard cup wherein an upper portion of a lower cup is uniquely joined to a lower portion of a substantially bottomless upper cup to provide enhanced integrity, insulative and other qualities.
This invention is concerned with cup making equipment for producing a two stage cup as shown and described in co-pending U.S. patent application Ser. No. 09/825,641 filed Apr. 4, 2001, now U.S. Pat. No. 6,382,449, which is hereby incorporated by reference. In this aforementioned patent application, there is set forth a two stage cup having a lower section sized to fit a standard vehicle cup holder, and an upper section with a larger volume than the lower section. More specifically, an upper cup and a lower cup are joined in a manner which provides improved insulative qualities and structural integrity. Such a finished cup is extremely versatile and can be used with hot and cold beverages as well as foodstuffs.
The assignee of the instant application, Paper Machinery Corporation of Milwaukee, Wis. U.S.A., is the manufacturer of paperboard cup making machines used to make a variety of cups and containers such as the upper cup and the lower cup discussed above. A typical cup machine for making paperboard cups, for instance, includes a turret having a plurality of mandrels about which the containers are formed. The turret sequentially rotates the mandrels into cooperation with a variety of work-stations station where numerous cup forming procedures occur.
In an exemplary procedure, a circular bottom blank is cut out at one work-station station and attached to the end of a mandrel by a vacuum applied through the mandrel. During this procedure, the outside edge or lip of the bottom blank is folded downwardly. At a subsequent work station, a sidewall blank is wrapped around the mandrel. The sidewall blank is heated and sealed along a seam which runs generally longitudinally along the side of the cup. Typically, the paperboard is coated with a thermoplastic material, such as polyethylene, so the blanks may be heated and sealed together. The sidewall blank extends transversely to the bottom blank except along the lip which runs approximately parallel with the sidewall blank. In some applications, the sidewall blank includes a flap extending beyond the lip of the bottom blank, and this flap is bent over the lip. At a bottom finishing station, the flap is pressed against the lip from an inside recessed area of the bottom of the cup. By heating the polyethylene and firmly pressing the sidewall, sidewall flap, and bottom flap lip together, a seal is formed and the cup is provided with a sturdy bottom region having a recessed area. There also may be other work stations where various additional cup forming procedures are carried out. For example, one station may be used to provide a curl at the top of the cup to provide a more functional drinking container and a better appearance.
As discussed in the ""641 application, prior art two stage containers used to fit standard vehicle cup holders are molded from thermoplastic and suffer from several draw backs. These include inefficient insulating quality, susceptibility to deformation upon microwaving, less than optimal biodegradability and a restricted ability to accept printing.
It would be desirable to produce a two stage cup which can be securely accommodated in a standard vehicle cup holder and overcomes the prior art deficiencies by modifying existing cup making equipment and adding a sealing and assembly machine which enables mass production at a reasonable cost.
It is a general object of the present invention to provide an automated system for forming a two stage cup preferably formed of paperboard having a lower section sized to fit a standard vehicle cup holder, and an upper section with a larger volume than the lower section.
It is one object of the present invention to provide an automated system for forming a two stage cup which makes use of existing cup making equipment.
It is also an object of the present invention to provide an automated system for forming a two stage cup which employs a sonic sealing assembly machine.
It is a further object of the present invention to provide an automated system for forming a two stage cup comprised of a bottomed lower cup and a substantially bottomless upper cup.
It is an additional object of the present invention to provide an automated system for efficiently forming a two stage cup at high volume speeds with minimal down time.
It is another object of the present invention to provide a method of utilizing cup making equipment to form a two stage cup.
In one aspect of the invention, an automated cup making machine is provided for forming a two stage cup having an upper cup disposed upon a lower cup. An upper cup making machine is provided for forming an upper cup having an upper cup sidewall and an upper cup bottom wall disposed generally transversely to the upper cup sidewall and punched out to define a bottom wall annular border extending radially inwardly from the upper cup sidewall, the upper cup sidewall having an outwardly curled top edge. A lower cup making machine is provided for forming a lower cup having a lower cup sidewall and a bottom wall disposed generally transversely to the lower cup sidewall, the lower cup sidewall having a curled top edge. A sealing and assembly machine is provided for receiving the upper cup from the upper cup making machine, and the lower cup from the lower cup making machine, for aligning the upper cup with the lower cup, one above the other, and flattening the lower cup curled top edge such that the upper cup bottom wall annular border lies in overlapping relationship with the lower cup flattened top edge and for sonic sealing the annular border to the flattened top edge to form a finished two stage cup.
The upper cup making machine has a bottom maker which removes a central portion of the upper cup bottom wall. The sealing and assembly machine includes a framework, a turret rotatably mounted to the framework, a lower cup feeding station mounted on the framework and an upper cup feeding station mounted on the framework. The sealing and assembly machine further includes a seam orientation station, a rim pre-flattening station for pre-flattening the lower cup curled top edge and a sonic sealing station for sealing the upper cup and the lower cup together. A blow off station is provided for removing the finished two stage cup. The turret rotates the upper cup and the lower cup sequentially to the seam orientation station, the rim pre-flattening station, the sonic sealing station, and the cup blow off station. The sonic sealing station includes a fixture for sealing the upper cup together with the lower cup. The fixture is comprised of a lower anvil for supporting the upper cup in inverted fashion, an upper anvil for supporting the lower cup in inverted fashion on top of the upper cup (that is, the rim of the lower cup is under the upper cup) and a sonic horn engagable with the overlapping upper cup bottom wall annular border and the lower cup flattened top edge. The sonic horn is disposed between a flap of the upper cup and the upper portion of the lower cup sidewall to effect sealing between the upper cup and the lower cup.
In another aspect of the invention, there is set forth a method of manufacturing a two stage cup including the steps of
a) providing an upper cup making machine for forming an upper cup having an upper cup sidewall with a side seam and an upper cup bottom wall punched out to define a bottom wall annular border extending radially inwardly from the upper cup sidewall;
b) providing a lower cup making machine for forming a lower cup having a lower cup sidewall with a side seam and a lower cup bottom wall extending generally transversely to the lower cup sidewall, the lower cup having a top edge; and
c) providing a sealing and assembling machine for aligning and joining the upper cup and the lower cup such that the bottom wall annular border is in overlapping relationship with the lower cup top edge. The step c) includes the step of placing the lower cup upon the upper cup such that the respective side seams are aligned. Step c) further includes the step of pre-flattening the lower cup top edge. Step c) also includes the step of providing a sonic sealing fixture for joining the upper cup bottom wall annular border with the lower cup flattened top edge. The step c) also includes the step of providing a rotatable turret for sequentially moving an aligned upper cup and a lower cup in a circular path past a number of processing stations.
The invention also contemplates cup making equipment for making a first cup having one volume and a second cup of a volume lesser than the first cup, both the first cup and the second cup having a sidewall with a top edge and a bottom wall extending generally transversely to the sidewall. The invention is improved wherein the cup making equipment is constructed and arranged to remove a portion of the bottom wall of the first cup to define a bottom wall annular border extending radially inwardly from the sidewall of the first cup. The cup making equipment is also constructed and arranged to flatten the top edge of the second cup, align the first cup with the second cup such that the flattened top edge of the second cup is in overlapping relationship with the bottom wall annular border of the first cup, and seal the flattened top edge of the bottom wall annular border to join the first cup and the second cup into a two stage cup having an insulated air gap between a lower portion of the first cup and an upper portion of the second cup.